package Thread;

//单例模式 , 懒汉模式的实现
class SingletonLazy{
    private static volatile SingletonLazy instance = null;

    private static Object locker = new Object();
    synchronized public static SingletonLazy getInstance(){
        if(instance == null){
            synchronized (locker){
                if(instance == null){
                    instance = new SingletonLazy();
                }
            }
        }
        return instance;
    }

    private SingletonLazy(){}
}

public class Demo28 {
    public static void main(String[] args) {
        SingletonLazy s1 = SingletonLazy.getInstance();
        SingletonLazy s2 = SingletonLazy.getInstance();
        System.out.println(s1 == s2);
    }
}
